A power source on an electronic product can be an AC-to-DC power supply or a DC-to-DC regulator. The AC-to-DC power supply is designed to supply a steady voltage to loads, and the DC-to-DC regulator may be used to supply a steady voltage that differs from the voltage supplied from the power supply. The power source may also have remote sensing capability that allows it to output a supply voltage based on a sensed voltage that is provided to the power source in a feedback loop.
For example, a power source provides a nominal supply voltage of 1.5V to a microprocessor device on a printed circuit board (PCB). The microprocessor device should also experience a nominal voltage of 1.5V. The voltage at the microprocessor device, however, is sensed to be only 1.4V. This means that there is a voltage drop of 0.1V from the power source to the microprocessor device. If the power source has a remote sensing capability and senses the voltage at the microprocessor device, a sensed voltage of 1.4V is fed back to the power source. To compensate for the voltage drop of 0.1V, the voltage regulator outputs a supply voltage of 1.6V. As the voltage level at the microprocessor device fluctuates, the power source adjusts the outputted supply voltage accordingly.
When a power source supplies a single device, the voltage fed back to the voltage regulator is usually sensed at the location of the single device. For example, if the single device is a microprocessor, the sense location would be at the microprocessor.
As systems become more complex, however, a single power source is often used to supply multiple devices. With multiple devices, it is difficult to ascertain an optimal sense location that will enable the power source to output a supply voltage that achieves the best compromise between the voltage needs of the multiple devices. In some cases, there may also be multiple power sources that supply voltages to the multiple devices. Currently, designers of PCBs determine sense locations by guessing a sense location based on experience and the current consumptions of the devices supplied by a power source or power sources. This often results in sub-optimal sense locations and power sources supplying voltages that are too high or too low.
Thus, there is a need for a better way to determine an optimal sense location for sensing the feedback voltage to a power source so that the supplied devices are supplied with voltages close to nominal voltages.